Section IV Model 112A
Paragraphs 4-40 to 4-42
4-40. If C19, C20, C21, or C22 have too much capac- 4-41. SERVICING ETCHED CIRCUIT BOARDS.
ity or if the associated resistors R52, R53, R56, and
R57 have low resistance, there will be overshoot on 4-42. The Model 211A is supplied with single-sided
the square wave. If the capacity of any of these capac- etched circuit boards; i. e., conductive material is
located only on one side of the boards. Funneled eye-
itors is low or the associated resistors have for some lets insure good electrical contact between component
reason increased in resistance, there will be under- leads and conductor. When servicing these boards,
shoot or rounding of the corner of the leading edge of
the square wave. Before any changes in these parts the following general rules should be followed:
are made, however, every effort should be made to
correct the trouble with good tubes as this is the nor - a. DO NOT APPLY EXCESSIVE HEAT to compo-
nents or conductor.
ma1 reason for poor waveshape. Unless these parts
have changed value, these circuits should not need b. To remove damaged components, clip leads near
adjustment. No adjustment should attemptedunless be component; then apply heat and remove leads with a
a 30 megacycle oscilloscope is available to determine straight upward motion. .
when the compensation is correct.
c. Use a toothpick or wooden splinter clean to compo-
CAUTION nent mounting holes before installingnew components.
To avoid accidental damage, always turn off d. APPLY SOLDER FROM CONDUCTOR SIDE of
power before removing or installing circuit board to insure good contact between eyelets, comp.0-
board assemblies. nent lead, and conductor.
SYNCHROSCOPE 211 A
AT FAULT AT FAULT RO
Figure 4-5. 75-ohm Output Waveform which has Defects on Positive Portion,
as Observed with a DC Coupled Oscilloscope |
ACEC
